Oral Treatment Devices

Abstract

The present invention provides an oral treatment unit or an assembly of multiple oral treatment units adapted to be inserted into the oral cavity for area-limiting and modulating an electromagnetic field having a frequency in the range of 100 kHz to 300 MHz, the oral treatment unit comprising a base unit combined with the oral treatment unit to form part of an oral cleaning device and a first cleaning element coupled to the oral treatment unit. The oral treatment unit further comprises a material structure coupled to the oral treatment unit adapted to receive an initial electromagnetic field and output a focused electromagnetic field, the material structure having a passive electromagnetic field focusing function that focuses the received initial electromagnetic field to a near-field region of the material structure. A further aspect of the present invention provides an oral treatment unit or an assembly of multiple oral treatment units adapted to be inserted into the oral cavity for area-limiting and modulating an electromagnetic field having a frequency in the range of 1 MHz to 300 GHz, the oral treatment unit comprising a base unit combined with the oral treatment unit to form part of an oral cleaning device and a first cleaning element coupled to the oral treatment unit. The oral treatment unit further comprises an electromagnetic field focusing element adapted to receive the electromagnetic field having the initial frequency and output a focused electromagnetic field. The electromagnetic field focusing element comprises a first material structure having a first passive electromagnetic field focusing function that performs one or more of an attenuation rate control function or a propagation direction correction function on the electromagnetic field in a near field region of the first material structure to area-confine the modulated electromagnetic field to a given distance from the first material structure, and the electromagnetic field focusing element has a modulation function that modulates the area-confined electromagnetic field, thereby producing a modulated electromagnetic field.

Description

[Technical field]

[0001] The present invention relates to the field of oral cleaning devices, and more particularly to the field of oral cleaning devices that utilize electromagnetic fields. [Background technology]

[0002] The field of oral cleaning and hygiene is under constant development, especially in the field of electric toothbrushes and other oral cleaning devices such as brushing mouthpieces, integrated brushing and flossing devices or irrigators.

[0003] One such development is the inclusion of a means for generating a radio frequency (RF) electromagnetic field, referred to herein as an RF field, in the vicinity of the user's teeth and gums.

[0004] FIG. 1 shows simulation results for a simplified example of an existing oral treatment unit 10 comprising a non-conductive dielectric barrier 12, a first RF electrode 13 and a second RF electrode 14.

[0005] In use, an electrical signal in the radio frequency range is provided to the first and second RF electrodes, thereby generating an RF field 15 between the two electrodes. Because RF field lines cannot pass through the non-conductive barrier 12, the RF field is shaped around the dielectric barrier and redirected / refracted towards the user's teeth and gums.

[0006] In other words, the example of FIG. 1 delivers an RF field using three elements: two exposed metal conductors and one insulator, as well as a non-conductive barrier that is needed to shape and redirect the electromagnetic field near the teeth.

[0007] However, the example shown in Figure 1 requires many separate electrically powered components that increase manufacturing complexity, as well as exposed metal electrical contacts located in the user's mouth, the latter creating a higher risk of injury and oral discomfort due to exposed mechanically sharp and electrically active elements in the oral cavity. Moreover, existing solutions only provide crude control of the area limitations of the RF field and are prone to electromagnetic energy leakage in the form of radiation. Summary of the Invention [Problem to be solved by the invention]

[0008] Thus, a need exists for a means of producing improved area containment and focusing of an RF field that uses a reduced number of components and does not require exposed metal contacts to be located within the oral cavity.

[0009] Additionally, means for generating a radio frequency (RF) electromagnetic field, referred to herein as an RF field, near a user's teeth and gums have size limitations in order to fit comfortably within the oral cavity.

[0010] Therefore, there is a further need for a means of generating an area-limited RF field using components that have a reduced form factor for placement within the oral cavity.

[0011] US Patent No. 10,201,701 discloses an oral cleaning device having an RF generator in the handle portion that delivers RF energy to electrodes on the brush head adjacent to the bristles. [Means for solving the problem]

[0012] The invention is defined by the claims.

[0013] According to an embodiment in accordance with an aspect of the present invention, there is provided an oral treatment unit adapted for insertion into an oral cavity of a user, for regionally limiting an electromagnetic field having a frequency in the range of 100 kHz to 300 MHz, the oral treatment unit comprising: a first cleaning element coupled or integral with the oral treatment unit; a material structure adapted to receive an initial electromagnetic field and output a focused electromagnetic field, the material structure being coupled or integrated with the oral treatment unit, the material structure having a passive electromagnetic field focusing function that limits the received initial electromagnetic field to a near field region of the material structure; An oral treatment unit is provided comprising:

[0014] The material structure is A negative or near-zero effective dielectric constant; with negative or near-zero effective permeability; Negative or near-zero refractive index The present invention has one or more of the following:

[0015] The oral treatment unit provides a means for focusing an electromagnetic field, e.g., having a frequency in the radio frequency (RF) range, within a near field region of a material structure to assist in cleaning a user's mouth by producing a region-limited electromagnetic (EM) field in the area of ​​the user's teeth or gums.

[0016] In this manner, a focused EM field is generated without the need for a dielectric barrier or any exposed electrical conductors within the oral treatment unit that contact the user's mouth.

[0017] Furthermore, since the focusing function is a property of the material structure, the shape and focus of the EM field may be adjusted according to any given embodiment of the oral treatment unit.

[0018] In an embodiment, the material structure comprises a plurality of unit cells, optionally arranged in an array.

[0019] In this way, if the dimensions of the unit cell are significantly smaller than the wavelength of the applied EM field, the material structure acts as a single element whose overall electromagnetic properties modify the EM field, and the resulting confinement, distribution and shaping of the EM field results from the homogenization of the individual properties within the unit cell.

[0020] In an embodiment, the oral treatment unit further comprises a second cleaning element, the material structure forming at least a portion or all of the second cleaning element.

[0021] In this way, the material structure contributes to both the mechanical cleaning action and the area restriction or shaping of the EM field, thereby performing two functions.

[0022] In an embodiment, the unit cell comprises: Planar conductive spiral structure; Planar conductive ring structure; Planar conductive meander line structure; 3D conductive spiral structure; 3D conductive ring structures; or 3D conductive meandering line structure Equipped with.

[0023] In this way, the EM field received by the material structure is transformed into an evanescent wave.

[0024] In an embodiment, the material structure comprises: a first unit cell adapted to receive and focus a first electromagnetic field having a first frequency within a first frequency range; a second unit cell adapted to receive and focus a second electromagnetic field having a second frequency within a second frequency range different from the first frequency range; Equipped with.

[0025] In this manner, multiple EM fields having different frequencies can be provided without the need to activate different device operating modes.

[0026] In an embodiment, the oral treatment unit further comprises one or more transmitter coils adapted to generate an initial electromagnetic field that is received by the material structure.

[0027] In an embodiment, the oral treatment unit further comprises a multi-harmonic transmitter coil adapted to generate a first electromagnetic field within a first frequency range that is received by the first unit cell and a second electromagnetic field within a second frequency range that is received by the second unit cell.

[0028] In an embodiment, the oral treatment unit further comprises a first transmitter coil adapted to generate an electromagnetic field having a first frequency within a first frequency range, and a second transmitter coil adapted to generate an electromagnetic field having a second frequency within a second frequency range.

[0029] In an embodiment, the coil loops of the transmitter coil and the helical structures of the unit cells are aligned parallel and / or concentrically.

[0030] In this way, the coupling between the transmitter coil and the unit cell or material structure is improved.

[0031] According to an embodiment of the present invention, there is provided a base unit for use in combination with the oral treatment unit described above, the base unit comprising: Power supply and; an electrical signal generating unit adapted to generate an electrical signal having a frequency within a given frequency range, the electrical signal generating unit being coupled to a power source; one or more transmitter coils adapted to generate and transmit at least one electromagnetic field having a frequency within a given frequency range to the oral treatment unit, the transmitter coils being in communication with the electrical signal generator; A base unit is provided comprising:

[0032] According to an embodiment of the present invention, there is provided a base unit for use in combination with the oral treatment unit described above, the base unit comprising: Power supply and; an electrical signal generating unit adapted to generate an electrical drive signal having a frequency within a given frequency range for supplying to a transmitter coil of the oral treatment unit, the electrical signal generating unit being coupled to a power source; A base unit is provided comprising:

[0033] According to an embodiment according to an aspect of the present invention, one or more of the oral treatment units described above; The base unit described above An oral cleaning device is provided, comprising: an oral treatment unit adapted to be temporarily coupled to a base unit.

[0034] According to an embodiment according to an aspect of the present invention, one or more of the oral treatment units described above; The base unit described above Equipped with An oral cleaning device is provided, wherein the oral treatment unit is adapted to be temporarily coupled to a base unit, the oral treatment unit further comprising a first electrical contact and the base unit further comprising a second electrical contact, the first electrical contact and the second electrical contact coming into contact when the oral treatment unit is coupled to the base unit.

[0035] In embodiments, the oral treatment unit is an electric toothbrush head or part of an electric toothbrush head, the electric toothbrush head optionally comprising a fluid ejection nozzle and the base unit is an electric toothbrush handle, or one or more of the oral treatment units described above are arranged to form at least a part of the brushing arch of an oral treatment mouthpiece and the base unit is an electric mouthpiece handle.

[0036] According to an embodiment in accordance with a further aspect of the present invention there is provided an oral treatment unit adapted to be inserted into an oral cavity of a user for area confinement and modulation of an electromagnetic field having a frequency in the range of 1 MHz to 300 GHz, the oral treatment unit comprising: a first cleaning element coupled or integral with the oral treatment unit; an electromagnetic field focusing element coupled or integral to the oral treatment unit, the electromagnetic field focusing element adapted to receive an electromagnetic field having an initial frequency and to output a focused electromagnetic field, the electromagnetic field focusing element comprising a first material structure, the first material structure comprising: a damping rate control function in the near field region of the first material structure; or Correction of propagation direction for electromagnetic fields an electromagnetic field focusing element having a first passive electromagnetic field focusing function that area-confines a received electromagnetic field to a given distance from the first material structure by performing one or more of the following: Equipped with The electromagnetic field focusing element modulates the area-limited electromagnetic field, thereby providing an oral treatment unit having a modulation function to produce a modulated electromagnetic field.

[0037] Oral treatment units with electromagnetic field focusing elements provide a means for modulating the incoming electromagnetic field to a desired frequency range, such as the radio frequency range.

[0038] Although electromagnetic fields having frequencies in the radio frequency range are desirable for oral treatment applications, material structures having passive electromagnetic field focusing capabilities tuned for radio frequencies are not suitable for oral treatment application applications, for example, due to the form factor or manufacturing cost of the material structures. Material structures having passive electromagnetic field focusing capabilities tuned for frequencies greater than radio frequencies, such as GHz frequencies, can be manufactured into smaller form factors using conventional manufacturing techniques, thereby reducing the cost of manufacturing, but electromagnetic fields having frequencies in the GHz range are not always optimal for oral treatment applications.

[0039] Therefore, by providing an oral treatment unit having an electromagnetic field focusing element with a modulation function, the oral treatment unit includes a material structure tailored to focus and area confine the electromagnetic field to a high electromagnetic frequency range, such as the GHz frequency range, and the modulation function modulates the frequency of the focused EM field to bring the frequency into the radio frequency range for use in treating the oral cavity.

[0040] In an embodiment, the modulation function includes a frequency downshift function that modulates the initial frequency of the area-limited electromagnetic field, thereby generating a modulated and area-limited electromagnetic field having a modulated frequency within a desired frequency range that is lower than the initial frequency.

[0041] In this manner, the initial frequency of the area-limited EM field, for example in the GHz range, is shifted down to a desired frequency range, such as the radio frequency range.

[0042] In an embodiment, the modulation function is and frequency of area-limited electromagnetic fields; Area-limited electromagnetic field amplitude and; Phase of the region-limited electromagnetic field and The optical fiber is adapted to modulate one or more of the optical fibers.

[0043] In this manner, the initial EM field can be modulated in any desired manner depending on the application.

[0044] In an embodiment, the electromagnetic field focusing element comprises a mechanical actuator for performing a modulation function, the mechanical actuator adapted to impart a mechanical vibration to the first material structure, optionally the mechanical actuator comprising: CMUT and; with electroactive polymers; A ferroelectric polymer actuator; A piezoelectric actuator; Piezoelectric bending actuators; MEMS tilt motion device The present invention includes one or more of the following:

[0045] The passive electromagnetic field focusing function of the material structure is controlled by the internal resonance of the material structure. By providing a mechanical vibration to the material structure by a mechanical actuator, the internal resonance of the material structure is modulated based on the frequency of the mechanical vibration. The mechanical actuator has a nonlinear performance, for example, by design or by including an additional electrical diode component.

[0046] In an embodiment, the mechanical actuator comprises a flexible component (335) and the first material structure is incorporated into the mechanical actuator.

[0047] In this way, the mechanical actuation unit and the material structure are formed as a single component that performs both the signal modulation and electromagnetic field focusing functions.

[0048] In an embodiment, the first material structure has a second passive electromagnetic field focusing function, the first passive electromagnetic field focusing function acting on a first frequency component of the received electromagnetic field and the second passive electromagnetic field focusing function acting on a second frequency component of the received electromagnetic field.

[0049] In this manner, both the first and second frequency components are focused and area confined within the first material structure, thereby producing frequency mixing, also referred to as heterodyning, thereby modulating the frequency of the received electromagnetic field.

[0050] In an embodiment, the electromagnetic field focusing element comprises a second material structure, the second material structure having a second passive electromagnetic field focusing function, the first passive electromagnetic field focusing function acting on a first frequency component of the received electromagnetic field and the second passive electromagnetic field focusing function acting on a second frequency component of the received electromagnetic field, optionally the first material structure positioned relative to the second material structure such that the focused first frequency component and the focused second frequency component are domain confined within both the first material structure and the second material structure, thereby generating frequency mixing between the focused first frequency component of the received electromagnetic field and the focused second frequency component of the received electromagnetic field, thereby performing a frequency modulation function.

[0051] In this manner, both the first and second frequency components are focused and area confined within the first and second material structures, thereby producing frequency mixing, also referred to as heterodyning, thereby modulating the frequency of the received electromagnetic field.

[0052] In an embodiment, the first material structure and / or the second material structure have a time delay function that imparts a time domain waveform to the focused electromagnetic field.

[0053] In this manner, a time domain waveform is imparted to the electromagnetic field to deliver, for example, a series of focused electromagnetic pulses having a given duty cycle.

[0054] In an embodiment, the electromagnetic field focusing element comprises a non-linear electronic component adapted to perform a frequency modulation function on the received electromagnetic field, optionally comprising: With diode; With multiple diodes; MIM devices and; With transistors; Passive transistors and The present invention includes one or more of the following:

[0055] In an embodiment, the oral treatment unit further comprises one or more transmitter coils adapted to generate an electromagnetic field that is received by the electromagnetic field focusing element.

[0056] According to an embodiment of the present invention, there is provided a base unit for use in combination with the oral treatment unit described above, the base unit comprising: Power supply and; an electrical signal generating unit adapted to generate an electrical signal having a frequency within a given frequency range, the electrical signal generating unit being coupled to a power source; one or more transmitter coils adapted to generate and transmit at least one electromagnetic field having a frequency within a given frequency range to the oral treatment unit, the transmitter coils being in communication with the electrical signal generator; A base unit is provided comprising:

[0057] According to an embodiment of the present invention, there is provided a base unit for use in combination with the oral treatment unit described above, the base unit comprising: Power supply and; an electrical signal generating unit adapted to generate an electrical drive signal having a frequency within a given frequency range for supplying to one or more transmitter coils of the oral treatment unit, the electrical signal generating unit being coupled to a power source; A base unit is provided comprising:

[0058] According to an embodiment according to an aspect of the present invention, one or more of the oral treatment units described above; The base unit described above wherein the oral treatment unit is adapted to be temporarily coupled to the base unit.

[0059] According to an embodiment according to an aspect of the present invention, one or more of the oral treatment units described above; The base unit described above Equipped with An oral treatment device is provided, wherein the oral treatment unit is adapted to be temporarily coupled to the base unit, the oral treatment unit further comprising a first electrical contact and the base unit further comprising a second electrical contact, the first electrical contact and the second electrical contact coming into contact when the oral treatment unit is coupled to the base unit.

[0060] According to an embodiment of the present invention, there is provided an oral cleaning device as described above, comprising: The oral treatment unit is an electric toothbrush head or part of an electric toothbrush head, the electric toothbrush head optionally comprising a fluid ejection nozzle, and the base unit is an electric toothbrush handle, or An oral cleaning device is provided in which one or more oral treatment units are arranged to form at least a portion of an arcuate portion of an oral treatment mouthpiece, and the base unit is a motorized mouthpiece handle.

[0061] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0062] For a better understanding of the present invention, and to show more clearly how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which: [Brief description of the drawings]

[0063] [Figure 1] FIG. 1 shows a schematic diagram of an example of a simulation result of an existing oral treatment unit. [Diagram 2] 1 shows a schematic diagram of an oral treatment unit for treating a user's oral cavity according to an aspect of the present invention; [Figure 3a] FIG. 3 shows a schematic diagram of an exemplary unit cell of the material structure shown in FIG. 2. [Figure 3b] FIG. 3b shows the corresponding RLC equivalent resonant circuit for the unit cell of FIG. 3a. [Figure 4] 1 illustrates a further embodiment of an oral treatment unit according to an aspect of the present invention. [Diagram 5] 1 illustrates a further embodiment of an oral treatment unit according to an aspect of the present invention. [Figure 6] 1 illustrates a further embodiment of an oral treatment unit according to an aspect of the present invention. [Figure 7] 1 shows an example of an oral cleaning device according to an aspect of the present invention. [Figure 8] An embodiment is shown in which the oral cleaning device is a cleaning or treatment mouthpiece. [Figure 9] 1 illustrates a method for using an oral cleaning device according to an embodiment of the present invention. [Figure 10] 1 illustrates an example of an oral treatment unit with modulation functionality according to an aspect of the present invention. [Figure 11] 13 illustrates a further embodiment of an oral treatment unit with modulation functionality according to an aspect of the present invention. [Figure 12] 13 illustrates a further embodiment of an oral treatment unit with modulation functionality according to an aspect of the present invention. [Figure 13] 1 shows an example of a unit cell of a material structure capable of operating on two different frequency components. [Figure 14] 4 illustrates a method for using an oral cleaning device according to a further aspect of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] The present invention will now be described with reference to the drawings.

[0065] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the devices, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the drawings are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to denote the same or similar parts.

[0066] The present invention provides an oral treatment unit or an assembly of multiple oral treatment units adapted to be inserted into an oral cavity for region-confining an electromagnetic field having a frequency in the range of 100 kHz to 300 MHz, comprising a first cleaning element coupled to the oral treatment unit in combination with a base unit to form part of an oral cleaning device, the oral treatment unit further comprising a material structure coupled to the oral treatment unit adapted to receive an initial electromagnetic field and output a focused electromagnetic field, the material structure having a passive electromagnetic field focusing function for focusing the received initial electromagnetic field into a near field region of the material structure.

[0067] A further aspect of the present invention provides an oral treatment unit or an assembly of multiple oral treatment units adapted to be inserted into the mouth for area-confining and modulating an electromagnetic field having a frequency in the range of 1 MHz to 300 GHz, which in combination with a base unit forms part of an oral cleaning device and includes a first cleaning element coupled to the oral treatment unit. The oral treatment unit further comprises an electromagnetic field focusing element adapted to receive the electromagnetic field having the initial frequency and output a focused electromagnetic field. The electromagnetic field focusing element comprises a first material structure, which has a first passive electromagnetic field focusing function that area-confines the modulated electromagnetic field to a given distance from the first material structure by performing one or more of the following functions: attenuation rate control function in the near field region of the first material structure; or a propagation direction correction function for the electromagnetic field. The electromagnetic field focusing element has a modulation function that modulates the area-confined electromagnetic field, thereby generating a modulated electromagnetic field.

[0068] 2 shows a schematic diagram of an oral treatment unit 20 for treating a user's oral cavity, such as cleaning any of the user's teeth, gums, or tongue, in accordance with an embodiment of the present invention.

[0069] The oral treatment unit 20 comprises a platen 22, which is defined as a base piece for receiving various components forming the device or subunits of the device shaped according to a desired embodiment. For example, the platen is planar or curved. The oral treatment device comprises one or more cleaning elements 24 coupled to the oral treatment device. The oral treatment unit forms part of any suitable oral treatment device, such as a brushing mouthpiece. In the example shown in FIG. 2, the oral treatment unit is part of the head of a toothbrush, such as an electric toothbrush, and the cleaning elements are toothbrush bristles. Alternative oral treatment units and cleaning elements are further described below.

[0070] The oral treatment unit 20 further comprises a material structure 26 comprising a plurality of unit cells, which is coupled to the oral treatment device and adapted to receive an electromagnetic field 28 and output a focused electromagnetic field 30. The material structure has a passive radio frequency focusing function that focuses a received radio frequency signal into a near field region of the material structure.

[0071] The material structure is an example of a so-called metamaterial, and more specifically, an electromagnetic metamaterial. Using computational modeling and algorithmic design processes, electromagnetic metamaterials can be designed with tunable and exotic electromagnetic properties, such as negative or near-zero effective permittivity, negative or near-zero effective permeability, and negative or near-zero refractive index.

[0072] Metamaterials are an emerging technology and are defined as artificial materials that are influenced not by their composition but by their structure, i.e., the geometric arrangement of one or more materials and unit cells. Metamaterials are designed to enable features not available in naturally occurring materials, such as negative refractive index. Metamaterials, such as material structure 26, consist of an array of unit cells, the characteristic size of which, as discussed further below, is significantly smaller than the signal wavelength utilized by the devices described herein. Details regarding an exemplary unit cell of a material structure are discussed below with reference to FIG. 3.

[0073] By tailoring the effective properties of the metamaterial according to a desired electromagnetic field focusing function, electromagnetic waves and / or fields can be manipulated by absorbing, blocking, enhancing, bending or reflecting the waves.

[0074] Electromagnetic metamaterials exhibit negative or near-zero effective permeability, negative or near-zero effective dielectric constant, or negative or near-zero refractive index, which occurs when both the dielectric constant and permeability of a material structure are simultaneously negative.

[0075] In general, a negative refractive index is desirable for EM field focusing. For EM fields with frequencies in the low MHz radio frequency (RF) range, only super-resolution in the near field, defined as less than one wavelength away from the source, is required. Furthermore, only one of the effective electromagnetic properties needs to be negative, since that is enough to enhance the evanescent waves to produce the focused RF electromagnetic field. In addition, in the low frequency quasi-static limit, i.e., for frequencies in the low MHz range, the electric and electromagnetic fields are largely separated, thereby simplifying material requirements.

[0076] The EM fields of interest in this invention have a wide range of frequencies, from the radio frequency (RF) range to microwaves, e.g., 100 kHz to 300 GHz, and the wavelengths are typically long, up to the meter range, which is particularly large for small devices such as oral cleaning devices. Thus, the unit cells of metamaterials are miniaturized to dimensions for the deep subwavelength regime. Currently, wavelength to unit cell size ratios of 2000 to 14400 are possible, allowing miniaturized, compact RF metamaterial structures suitable for oral care devices.

[0077] Figure 3a shows a schematic diagram of an example unit cell 40 in plan view, with a cross-sectional view 41 of the material structure shown in Figure 2. Figure 3b shows a simplified version of the corresponding RLC equivalent resonant circuit 50 for the unit cell 40 of Figure 3a.

[0078] The properties of the unit cell 40 shown in FIG. 3a are defined by several characteristic dimensions. These are the width of the conductive traces 42, the spacing between the conductive traces, and the side length of the central capacitive pad 44, which may be connected to a second central capacitive pad (not shown) at the bottom of the dielectric layer through the entire length of the dielectric layer 45. In some embodiments, the central capacitive pad 44 does not extend through the entire thickness of the dielectric layer 45. The EM field shaping and focusing effect of the meta-material is due to the negative effective electromagnetic parameters, such as the negative permeability, induced by the internal resonance within the unit cell. The internal resonance is defined by the design of the unit cell, which can be equivalently considered as a resonant RLC circuit shown in FIG. 3b, where the inductance and capacitance are a function of the geometric parameters of the unit cell in addition to the material parameters, such as the conductivity, permeability, and permittivity. Additional geometric parameters that affect the internal resonance of the unit cell include the number of turns, the side length of the rectangular coil, the unit cell size, and the distance between the different layers of the unit cell.

[0079] The unit cell further includes a dielectric layer 45, as shown by cross-sectional view 41. The dielectric layer may be formed of any suitable dielectric material. In an embodiment, the dielectric layer is constructed from a glass reinforced epoxy laminate material.

[0080] The RLC circuit shown in Fig. 3b corresponds to a quasi-static representation of the unit cell design. The inductance L is given by the self-inductance of the spiral, the capacitance C corresponds to the equivalent capacitance given by the sum of the total distributed capacitance between the parallel sidewalls (adjacent turns) and the vertical capacitor formed by the two rectangular conductive pads in the center of the unit cell, and the resistor R corresponds to the total resistance given by the sum of the resistance caused by the skin effect, the proximity losses caused by eddy currents, the sheet resistance of the metal wiring, and the dielectric losses. Higher order effects such as capacitive coupling between non-adjacent sidewalls are considered negligible.

[0081] The unit cell shown in FIG. 3a is an example of a planar helix resonator, which belongs to a group of metamaterials that exhibit negative or near-zero effective permeability, but negative or near-zero dielectric constants, or negative or near-zero refractive indices, are also realized. An example of this type of deep subwavelength metamaterial design for signals in the RF frequency range has a unit cell size a on the order of a~λ0 / 2000, where λ0 is the free-space wavelength and a is the characteristic size of the unit cell. The free-space wavelength for radio frequencies ranging between 3 MHz and 300 GHz is on the order of 1 millimeter to 100 meters. According to the above length fraction (λ0 / 2000), metamaterials with unit cell sizes of 0.5 μm~50 mm are designed, which is within the acceptable range for oral cleaning devices, such as in the platen of a toothbrush or the overall arch of a mouthpiece. According to the latest manufacturing technology of λ0 / 14400, even smaller unit cell sizes of 0.07 μm~7 mm are also designed.

[0082] The material structures or metamaterials described above having a negative or near-zero permittivity ε and / or a negative or near-zero magnetic permeability μ and / or a negative or near-zero refractive index are considered passive elements. Through structural design, the transmitted RF field is received by the material structure, thereby passing through the metamaterial and producing evanescent waves, i.e., oscillating electric and / or electromagnetic fields that do not propagate as electromagnetic waves but whose energy is concentrated spatially, particularly in the near-field regions of the material structure, or, in the case of frequencies in the GHz frequency range as discussed further below, redirected propagating waves.

[0083] As discussed above, metamaterials utilize internally resonating unit cells as building blocks. The underlying physical phenomenon of metamaterials results from the interaction between the internal resonances and the incoming electromagnetic waves, and the interaction between the unit cells, in the form of signal interference. Both interactions combine to create a band gap, a frequency band where ephemeral waves occur, facilitating wave damping. Having just one resonator (unit cell) only results in local damping (modal coupling at a particular frequency). Having a collective arrangement of resonators creates a global damping, hence the band gap and the corresponding ephemeral waves.

[0084] The unit cells within the material structures discussed herein are arranged in a 1D, 2D, or 3D periodic arrangement to form a regular array of unit cells.

[0085] Typically, computational simulations, called in silico modes, are used to design and measure the effective properties of proposed metamaterials. In silico designed materials can be manufactured in a straightforward manner using standard commercial manufacturing techniques such as thin-film fabrication processes, additive manufacturing, and printed circuit board photolithography.

[0086] Furthermore, meta-materials with specific target properties can be designed using existing design processes, such as machine learning, which can be used to explore a large parametric design space, and even to design meta-material structures from scratch. In addition, trial-and-error parametric search methods are used to optimize the design within a given set of constraints, such as designing an initial meta-material repeating unit with several adjustable parameters.

[0087] Emerging fabrication techniques such as 3D printing enable the rapid and cheap production of materials with complex internal structures, such as electromagnetic metamaterials.

[0088] 2, the oral treatment unit 20 with the material structure 26 described above provides a means to shape and focus a received radio frequency signal 28, for example, by a focusing function realized by an array of unit cells described above. In other words, the material structure 26 converts the propagating electromagnetic field 28 into an evanescent wave, thereby facilitating a passive EM field 30, or steers / redirects the propagating wave, for example, facilitating negative refraction, enabling field focusing 30.

[0089] 4 shows a further embodiment of an oral treatment unit 60 according to an aspect of the present invention. Reference numbers shared with FIG. 2 refer to similar features.

[0090] In the embodiment shown in FIG. 4, the oral treatment unit 60 further comprises an additional cleaning element 62, and the material structure 26 is incorporated into the additional cleaning element or is arranged to form the additional cleaning element 62 itself.

[0091] In other words, the additional cleaning elements 62 comprising metamaterial unit cells or metamaterial structures perform two functions: first, mechanical cleaning in conjunction with the unmodified cleaning elements 24, i.e., bristles, and second, EM field focusing due to the material structure incorporated in the additional cleaning elements 62, which comprise elongated, out-of-plane helical resonators or large diameter (wide) polymeric cleaning elements (e.g., bristles) embedded in a dielectric matrix, with planar helical metamaterial structures printed on top and bottom layers and connected by conductive wires that run through the length of the additional cleaning elements.

[0092] The basic design of the unit cell of the material structure is the same as that shown in Figure 3a, however, the meta-material is directly integrated into the cleaning elements, such as bristles, silicone posts, rubber pads, or prophy cups, thus adding additional cleaning functionality to the material structure.

[0093] 5 shows a further embodiment of an oral treatment unit 70 according to an aspect of the present invention. Reference numbers shared with FIG. 2 refer to similar features.

[0094] In the embodiment shown in FIG. 5, the oral treatment unit 70 further comprises a transmitter coil 72 adapted to transmit the electromagnetic field 28 that is received by the material structure 26 described above.

[0095] In this embodiment, a transmitter coil having a single loop or solenoid and transmitting the electromagnetic field is located within the platen of the oral treatment unit. The transmitter coil is integrated within the oral treatment unit or temporarily attached to the oral treatment unit. The material structure is located at a fixed distance from the transmitter coil, typically 0.5-5 mm. This distance is adjusted to optimize coupling between the transmitter coil and the material structure. The coil loop and the spiral meta-material are aligned concentrically in one plane, parallel and concentrically opposed to each other to efficiently couple the electromagnetic field into the meta-material.

[0096] As discussed above, the negative or near-zero effective properties of the metamaterial (dielectric constant, refractive index, and permeability) minimize leakage of electromagnetic fields and energy, facilitating better near-field focusing 30 towards the tooth or gum tissue.

[0097] FIG. 6 shows a further embodiment of an oral treatment unit 75 comprising a plurality of cleaning elements 76, an array of first unit cells 77 adapted to receive and area confine an electromagnetic field having a first frequency within a first frequency range, and an array of second unit cells 78 adapted to receive and area confine an electromagnetic field having a second frequency within a second frequency range different from the first frequency range.

[0098] In other words, the oral treatment unit or material structure comprises one or more arrays of multiple unit cells, each of which acts as an electromagnetic field lens tuned to a different operating frequency, thus facilitating multiple operating modes that can be realized in oral care devices such as toothbrushes and mouthpieces.

[0099] In this embodiment, either a multi-harmonic transmitter coil or multiple transmitter coils that transmit electromagnetic fields at multiple frequencies are incorporated into the oral treatment unit or base unit.

[0100] In other words, the oral treatment unit includes an array of meta-materials configured to provide enhanced EM field area restriction for different resonant frequencies, potentially enabling multiple modes of operation targeting specific zones in the oral cavity such as tartar, biofilm, stains, gum tissue, pockets, artificial teeth, orthodontics, etc. In this way, multiple EM energy levels can be provided as desired without the need to activate different device modes of operation. For example, the oral treatment unit implements the following modes, all requiring different device settings: cleaning mode for stain removal, tartar treatment mode, or gum health mode for treatment of gum pockets.

[0101] The oral treatment unit described above is part of or integral to an electric toothbrush head that is used in combination with a base unit, such as an electric toothbrush handle.

[0102] FIG. 7 illustrates an embodiment of an oral cleaning device 80 according to an aspect of the present invention, with the energy and signal transmission paths to a transmitter coil 72 inside the oral treatment unit 70 shown in dashed lines.

[0103] The oral cleaning device comprises the above-mentioned oral treatment unit 70 temporarily coupled to a base unit 82 comprising a power source 84 and an electrical signal generating unit 86 coupled to the power source and adapted to generate an electrical drive signal. The base unit further comprises a drive train / transmission technology or actuator for generating the mechanical motion required for cleaning (not shown).

[0104] Where the oral treatment unit comprises a transmitter coil 72, shown in dashed lines, the oral treatment unit is adapted to be temporarily coupled to a base unit, the oral treatment unit further comprising a first electrical contact 88 and the base unit further comprising a second electrical contact 90, the first electrical contact and the second electrical contact making contact when the oral treatment unit is coupled to the base unit. Thus, the electrical signal generated by the electrical signal generating unit 86 is provided to the transmitter coil 72 in the oral treatment unit to generate an electromagnetic field 28 that is received by the material structure 26 to produce the output focused EM field 30.

[0105] Alternatively, if the oral treatment unit does not include a transmitter coil, the base unit 82 includes a transmitter coil adapted to transmit an electromagnetic signal to the oral treatment unit and in communication with an electrical signal generator, in which case no electrical contact is required between the oral treatment unit and the base unit, and no electrically powered components are required within the oral treatment unit because the material construction is passive.

[0106] In the above described embodiments, the oral cleaning device has been described in the context of an electric toothbrush, however, the oral cleaning device may be any oral cleaning device such as a brushing / cleaning or treatment mouthpiece.

[0107] 8 shows an embodiment in which the oral cleaning device is a treatment mouthpiece 100, with a plurality of oral treatment units 115 coupled and arranged to form an arch 110. As described in detail above with reference to Figures 2 and 4, each of the oral treatment units 115 comprises a material structure adapted to produce a region-limited electromagnetic field from a received electromagnetic field provided from a plurality of transmitter coils 130 located in a base unit 135 temporarily coupled to the oral treatment units. The base unit 135 further comprises a power source 140 and a signal generator 145 as described above with reference to Figure 7.

[0108] FIG. 9 illustrates a method 200 for using the oral cleaning device described above.

[0109] The method begins at step 210 by providing one or more oral treatment units of an oral cleaning device in a user's mouth.

[0110] In step 220, a cleaning element of the oral treatment unit is used to clean the user's oral cavity using a mechanical cleaning motion and an electromagnetic signal is transmitted to the material structure of the oral treatment unit, thereby generating a focused radio frequency electromagnetic field in the vicinity of the gums or teeth in the user's oral cavity to assist in the cleaning process.

[0111] In the above-mentioned embodiment, the material structure of the oral cleaning unit is adapted to perform only a passive electromagnetic field focusing function for the received electromagnetic field. In the field of oral treatment, the focused electromagnetic field is preferably in the radio frequency range. Therefore, the above-mentioned embodiment is adapted to receive an electromagnetic field having a frequency in the radio frequency range, and in particular, the material structure or the unit cell of the material structure is adapted to focus and area-confine the electromagnetic field having a frequency in the radio frequency range.

[0112] However, material structures or unit cells with passive electromagnetic field focusing capabilities in the radio frequency range in a size and form factor suitable for use in oral treatment devices are difficult and costly to manufacture.

[0113] Following the fractional length equations described above, metamaterials adapted to focus electromagnetic fields having unit cell sizes between 0.5 μm and 150 mm and frequencies in the range of 1 MHz to 300 GHz can be designed using conventional design techniques, or as small as 0.07 μm to 21 mm using advanced design techniques, which are within the acceptable range for placement in an oral treatment device, such as the brush head of a toothbrush or the arch of a mouthpiece.

[0114] For metamaterials, the advantages of working with electromagnetic fields in the high electromagnetic frequency range instead of the low electromagnetic frequency range include a reduced form factor suitable for the inside of oral treatment devices and a wide range of metamaterial design possibilities, however EM fields operating at higher frequencies are not suitable for oral healthcare applications.

[0115] Therefore, the inventors have recognized that, in addition to the features and functions of the oral treatment unit, the base unit, and combinations thereof described above, the oral treatment unit may comprise an electromagnetic field focusing element adapted to receive an electromagnetic field having an initial frequency, for example, in the GHz frequency range, and output a focused electromagnetic field in the MHz frequency range, for example, in the radio frequency range. The electromagnetic field focusing element comprises a first material structure, such as the material structure described above, having a first passive electromagnetic field focusing function that performs one or more of an attenuation rate control function in the near field region of the first material structure, or a propagation direction correction function for the electromagnetic field, to area-confine the received electromagnetic field at the initial frequency to a given distance from the first material structure. The electromagnetic field focusing element then modulates the electromagnetic field by a modulation function, thereby generating a modulated and area-confined electromagnetic field.

[0116] The electromagnetic field focusing and modulation functions can be accomplished in a number of ways, some examples of which are described below. It should be noted that the oral treatment units described below may be incorporated into any of the systems described above.

[0117] The modulation function is adapted to modulate one or more of the frequency, amplitude or phase of the area-limited electromagnetic field. In certain embodiments, the modulation function includes a frequency downshift function that modulates an initial frequency of the area-limited electromagnetic field, thereby generating a modulated and area-limited electromagnetic field having a modulated frequency within a desired frequency range lower than the initial frequency.

[0118] In one embodiment, the electromagnetic field focusing element comprises a nonlinear electronic component, such as a diode, a plurality of diodes, a MIM device (which is a metal-insulator-metal device with the functionality of a back-to-back diode), a transistor, or a passive transistor, adapted to perform a frequency modulation function on the received electromagnetic field.

[0119] 10 shows a schematic diagram of an oral treatment unit 300 for treating a user's oral cavity, such as cleaning any of the user's teeth, gums, or tongue, in accordance with an embodiment of the present invention.

[0120] As in the previous embodiment, the oral treatment unit 300 comprises a platen 22 and one or more cleaning elements 24 coupled to the oral treatment unit. As above, the platen is defined as a base part for receiving various components forming a device or subunits of a device shaped according to a desired embodiment. For example, the platen is planar or curved. The oral treatment unit forms part of any suitable oral treatment device, such as a brushing mouthpiece. In the embodiment shown in FIG. 10, the oral treatment unit is part of the head of a toothbrush, such as an electric toothbrush, and the cleaning elements are toothbrush bristles. Alternative oral treatment units and cleaning elements are further described below.

[0121] 10, the oral treatment unit 300 further comprises an electromagnetic field focusing element 302 adapted to receive an electromagnetic field 304 having an initial frequency and to output a focused and modulated electromagnetic field 306. The electromagnetic field focusing element 302 comprises a material structure 308 comprising a plurality of unit cells, which is adapted to receive the electromagnetic field and to output a focused electromagnetic field 306. The material structure has a passive electromagnetic field focusing function that focuses the received electromagnetic field into a near field region of the material structure by field attenuation control or, alternatively, by redirection of the propagating electromagnetic wave, thereby facilitating negative refraction and focusing of the electromagnetic field.

[0122] Furthermore, the electromagnetic field focusing element 302 comprises a mechanical actuator 310 for performing a modulation function, such as a capacitive micromachined ultrasonic transducer (CMUT), a ferroelectric polymer actuator, an electroactive polymer, a vibrator or a digital mirror device, which is adapted to impart a mechanical vibration to the first material structure 308. The mechanical vibration imparted to the first material structure by the mechanical actuator shifts the internal resonance of the material structure or a unit cell of the material structure according to the frequency of the mechanical vibration. In this way, the frequency, amplitude or phase of the area-limited electromagnetic field is modulated according to the frequency of the mechanical vibration. For example, the phase of the area-limited electromagnetic field is modulated by providing two mechanical oscillators, each of which imparts a mechanical vibration to the first material structure.

[0123] In practice, one or more transmitter coils located in the oral treatment unit or in the associated base unit as described above are used to generate and radiate a high frequency electromagnetic field, for example in the GHz range, with two frequency components very close to each other. This electromagnetic field impinges on a material structure 308, which is coupled to a mechanical actuator 310 or a hybrid containing meta-material integrated in the mechanical actuator itself. The role of the material structure is to modify the electromagnetic field by controlling the decay rate, if a transient field is generated, or by controlling the focal length, if a backward wave is generated. The mechanical actuator operates in the MHz range and modifies the internal resonance of the unit cells forming the material structure, thereby providing a modulation of the electromagnetic field area-limited by the material structure.

[0124] In other words, one or more metamaterial unit cells are mechanically actuated to enable focusing at low frequencies, e.g., in the MHz range, electromagnetic field control, and controlled distances. The mechanical actuator has nonlinear performance, e.g., by design or by including additional electrical diode components.

[0125] Suitable mechanical actuators include piezoelectric elements, as crystalline actuators are one of the few solid-state (non-MEMS) actuators that can be made to vibrate in a desired frequency range, e.g., in the radio frequency MHz range. For example, an array of piezoelectric actuators is placed under the material structure and actuated at the desired MHz frequency.

[0126] For standard mechanical actuators, the linear working distance is smaller than required unless the actuator is large enough. As a result, the form factor of the electromagnetic field focusing element is larger than ideal for integration into an oral treatment unit. However, mechanical actuators with very compact forms are available, such as bending actuators with a bilayer of a thin piezoelectric layer on top of a thin substrate. In particular, in bending actuators, large working distances are achieved by bending perpendicular to the actuator, which results from the smaller linear expansion of the piezoelectric layer compared to the fixed substrate.

[0127] The material structure 308 is positioned a fixed distance from the transmitter coil and coil loop, and the unit cells of the material structure are aligned parallel to each other and concentrically in one plane to efficiently couple the electromagnetic field into the material structure. The material structure minimizes field leakage and provides controllable electromagnetic field focusing towards the tooth or gum tissue, while a mechanical actuator coupled to the electromagnetic meta-material provides signal modulation to deliver a controllable modulated electromagnetic field.

[0128] Similar to the embodiment described above with respect to FIG. 4, the material structures may also be incorporated into the cleaning element.

[0129] Alternatively, the mechanical actuator 310 comprises a microelectromechanical system (MEMS) tilting device, such as a digital mirror device (DMD), which uses electrostatic forces generated by electrodes to control the position of a small mirror. As a MEMS device, the DMD is positioned beneath a material structure to form a very thin form factor electromagnetic field focusing element that is integrated into the platen of the oral treatment unit.

[0130] The material structure is supported by, or alternatively deposited on, the DMD and oscillated at MHz frequencies, which is accomplished by rapidly tilting a mirror back and forth.

[0131] FIG. 11 shows an example of an oral treatment unit 320 comprising the electromagnetic field focusing element 325 described above, where the mechanical actuator 330 comprises a CMUT cell having a membrane 335, and the first material structure is partially or wholly integrated into the membrane.

[0132] Hybrid meta-CMUT cells, comprising meta-material unit cells and enabled for bending mechanical actuators, are adapted for non-linear actuation, for example, by design or by additional electrical diode components. The principles of incorporating material structures in the membrane of a CMUT apply to any suitable type of bending-based actuator, such as CMUT cells, ferroelectric polymers, or electroactive polymers (EAPs).

[0133] As discussed above, mechanical vibrations applied to a material structure modulate the electromagnetic field by causing a shift in the internal resonance of the unit cells.

[0134] FIG. 12 illustrates an example of an oral treatment unit 340 having an electromagnetic field focusing element 345 comprising a first material structure 350 and a second material structure 355 .

[0135] As described above, the first material structure has a first passive electromagnetic field focusing function, and similarly, the second material structure has a second passive electromagnetic field focusing function, the first and second focusing functions being tuned to act on different frequencies, such as first and second frequency components of the received electromagnetic field, respectively.

[0136] For example, one or more transmitter coils are used to generate and radiate a high frequency electromagnetic field, for example in the GHz range, with two frequency components very close to each other. The combination of these two frequency components in the first and second material structures results in heterodyning, also called frequency mixing, due to internal nonlinearities. The first and second material structures in the electromagnetic field focusing element area confine and focus the electromagnetic output field 306 by generating a transient field with a controllable decay rate for each of the two frequency components that mix to form the modulated electromagnetic field, or by modifying the propagation direction of the electromagnetic wave, for example through the generation of backward waves, thereby providing deep focal length control.

[0137] In other words, the oral treatment unit comprises two material structures, each composed of one or more unit cells designed to target one of two frequency components of the received electromagnetic field, and the two material structures are stacked adjacent to each other to provide area limitation and focusing of low frequency electromagnetic fields, e.g., electromagnetic fields in the radio frequency range.

[0138] By area-confining a first frequency component of the electromagnetic field within the electromagnetic field focusing element by a first material structure and area-confining a second frequency component of the electromagnetic field within the electromagnetic field focusing element by a second material structure, frequency mixing occurs between the two frequency components, thereby producing a modulated electromagnetic field having a lower frequency than the individual frequency components.

[0139] Furthermore, stacks of tuned material structures at different frequencies can be used to generate new time-domain waveforms that act as delay lines and act on electromagnetic fields, such as square waves to deliver electromagnetic impulses with a duty cycle.

[0140] Alternatively, rather than an electromagnetic field focusing element comprising a first material structure adapted to operate on a first frequency component of the electromagnetic field and a second material structure adapted to operate on a second frequency component of the electromagnetic field, similar results can be achieved with an electromagnetic field focusing element comprising a single material structure adapted to operate on both the first and second frequency components.

[0141] In other words, the material structure has a first passive electromagnetic field focusing function and a second passive electromagnetic field focusing function, the first passive electromagnetic field focusing function acting on a first frequency component of a received electromagnetic field and the second passive electromagnetic field focusing function acting on a second frequency component of the received electromagnetic field.

[0142] Figure 13 shows an example of a unit cell 360 of a material structure capable of operating on a first and second frequency component of an electromagnetic field. The unit cell 360 comprises a central conductor 365, a first conductor 370, and a second conductor 375. As can be seen from Figure 13, the first and second conductors have different spacing between themselves and the central conductor, which means that the unit cell has two different internal resonant frequencies, one for the first conductor (operating on the first frequency component) and one for the second conductor (operating on the second frequency component).

[0143] In this embodiment, the material structure domain confines both the first frequency component and the second frequency component within the first material structure, such that frequency mixing occurs between the two frequency components, thereby producing a modulated electromagnetic field having a lower frequency than the individual components.

[0144] FIG. 14 illustrates a method 400 for using an oral cleaning device comprising the electromagnetic field focusing element described above.

[0145] The method begins at step 410 by providing one or more oral treatment units of an oral cleaning device in a user's mouth.

[0146] In step 420, a cleaning element of the oral treatment unit is used to clean the user's oral cavity using a mechanical cleaning motion, and an initial electromagnetic field is transmitted to an electromagnetic field focusing element of the oral treatment unit, thereby generating a focused and modulated electromagnetic field near the gums or teeth in the user's oral cavity to assist in the cleaning process.

[0147] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprises" does not exclude other elements or steps, and the singular does not exclude a plurality.

[0148] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0149] It is noted that if the word "adapted" is used in the claims or description, the word "adapted" is intended to be equivalent to the word "configured."

[0150] Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An oral treatment device comprising: an oral treatment unit for inserting into an oral cavity, the oral treatment unit being adapted to limit an electromagnetic field having a frequency in a range of 100 kHz to 300 MHz; and a base unit for use in combination with the oral treatment unit, the oral treatment unit comprising: a first cleaning element coupled or integral with the oral treatment unit; a meta-material structure coupled or integrated with the oral treatment unit to receive an initial electromagnetic field and output a focused electromagnetic field, the meta-material structure comprising: A negative effective dielectric constant; Negative effective permeability; Negative refractive index and and 1. An oral treatment device comprising: a metamaterial structure having a passive electromagnetic field focusing function that area confines the received initial electromagnetic field to a near field region of the metamaterial structure, the metamaterial structure comprising a unit cell.

2. An oral treatment device as described in claim 1, wherein the unit cells are arranged in an array.

3. Each unit cell is Planar conductive spiral structure, A planar conductive ring structure, Planar conductive meandering line structure, 3D conductive spiral structure, a 3D conductive ring structure, or 3D conductive meandering line structure The oral treatment device of claim 1 or 2, comprising:

4. The oral treatment device of claim 1 , wherein the oral treatment unit further comprises a second cleaning element, the meta-material structure forming at least a portion or all of the second cleaning element.

5. The metamaterial structure comprises: a first unit cell for receiving and focusing a first electromagnetic field having a first frequency within a first frequency range; a second unit cell for receiving and focusing a second electromagnetic field having a second frequency within a second frequency range different from the first frequency range; 5. The oral treatment device of claim 1 , comprising:

6. The oral treatment device of claim 1 , wherein the oral treatment unit further comprises one or more transmitter coils that generate the initial electromagnetic field that is received by the meta-material structure.

7. 6. The oral treatment device of claim 5, further comprising a multi-harmonic transmitter coil that generates a first electromagnetic field within a first frequency range that is received by the first unit cell and a second electromagnetic field within a second frequency range that is received by the second unit cell.

8. The oral treatment device of claim 5, wherein the oral treatment unit further comprises a first transmitter coil generating an electromagnetic field having a first frequency within a first frequency range and a second transmitter coil generating an electromagnetic field having a second frequency within a second frequency range.

9. 9. The oral treatment device according to claim 6, wherein the unit cell has a helical structure, and the coil loops of the one or more transmitter coils and the helical structure of the unit cell are aligned parallel and / or concentrically.

10. The base unit comprises: Power supply, an electrical signal generating unit coupled to the power source for generating an electrical signal having a frequency within a given frequency range; one or more transmitter coils in communication with the electrical signal generating unit, the transmitter coils generating and transmitting at least one electromagnetic field having a frequency within the given frequency range to the oral treatment unit; 6. An oral treatment device according to claim 1 , comprising:

11. An oral treatment device as described in claim 10, wherein the oral treatment unit is temporarily coupled to the base unit.

12. The base unit comprises: Power supply, an electrical signal generating unit coupled to the power source for generating an electrical drive signal having a frequency within a given frequency range for supplying to the one or more transmitter coils of the oral treatment unit; 10. An oral treatment device according to claim 6, comprising:

13. The oral treatment device of claim 12, wherein the oral treatment unit is temporarily coupled to the base unit, the oral treatment unit further comprising a first electrical contact, and the base unit further comprising a second electrical contact, the first electrical contact and the second electrical contact coming into contact when the oral treatment unit is coupled to the base unit.

14. the oral treatment unit is an electric toothbrush head or part of an electric toothbrush head, the electric toothbrush head comprising a fluid ejection nozzle, and the base unit is an electric toothbrush handle; or 14. An oral treatment device according to any one of claims 1 to 13, wherein one or more oral treatment units are arranged to form at least a portion of an arcuate portion of an oral treatment mouthpiece, and the base unit is an electric mouthpiece handle.

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